The present invention relates generally to the field of agricultural implements, such as planters and other wide, foldable implements towed behind a work vehicle, such as a tractor.
A wide range of farm implements have been developed and are presently in use for tilling, planting, harvesting, and so forth. Seeders or planters, for example, are commonly towed behind tractors and may cover wide swaths of ground which may be tilled or untilled. Such devices typically open the soil, dispense seeds in the opening, and reclose the soil in a single operation. Seeds are commonly dispensed from seed tanks and distributed to row units by a distribution system. To make the seeding operation as efficient as possible, very wide swaths may be covered by extending wings on either side of a central section of the implement pulled by the tractor. These wings are commonly disposed in a “floating” arrangement during the planting operation, wherein hydraulic cylinders allow the implement to contact the soil with sufficient force to open the soil, dispense the seeds and close the soil. For transport, the tool bar, including the wings may be rotated to reduce the width of the implement.
For wide implements incorporating wings of the type described above, servicing may be greatly facilitated by the ability to raise the wings to better access row units attached to a tool bar on either side of the implement. Moreover, while the wings may generally “float” during planting, when the tool bar is raised, actuators maintain the wings in a raised position to avoid drooping or contact with the ground. Again, the wings are typically raised by hydraulic cylinders connected across a pivot joint. The wings may be left in a raised position for extended periods. While such operation does not normally pose difficulties, in certain situations the wings can slowly decline over longer period of time, such as overnight. There is a need, therefore, for improved techniques for controlling winged extensions on agricultural implements that avoids the inadvertent or undesirable lowering of the wings from raised positions.